The present invention generally relates to a checking method for a disk recording apparatus, and more particularly, to a disk recording checking method in which it is possible to judge at the time of recording whether or not a series of data have been recorded on predetermined sectors of a recording track of on a disk.
Conventionally, in a disk recording apparatus in which recording is performed on a disklike recording medium having a radially coaxial or spiral recording track divided into a predetermined plural number of sectors each acting as a recording unit, it has been a common practice that where recording is performed continuously on a plurality of the sectors, a check as to whether or not the recording has been performed properly is carried out by reading the contents in each of the sectors each time recording has been performed in each of the sectors. This known recording method has been disadvantageous in that it is difficult to reduce the recording time due to the waiting time required for rotating the disk.
In a prior art sector data validating method for validating data of sectors of a recording track on a magneto-optical disk, etc., at the time of reading immediately after the writing (referred to as "RAW" (Read After Write), one sector is divided into a plurality of code sequences. Each of the code sequences is constituted by a data portion and an error-checking code portion. In this arrangement, if the error-checking code portion is made larger in size in each of the code sequences, more errors in the data portion can be dealt with by the error-checking code portion. However, data efficiency drops due to the increase of the ratio of the error-checking code portion to each of the code sequences. Therefore, the ratio between the data portion and the error-checking code portion in each of the code sequences is determined by considering the characteristics of the recording medium, the error correcting method, etc.
In the prior art sector data validating method, the data of the sector is regarded as being valid if the total number of errors in the sector is not more than the total number of correctable errors in the error-checking code portions. However, where the number of errors in the sector is approximate to the limit of the correctable errors in the error-checking code portions during a check at the time of reading immediately after writing, i.e., during a RAW check, such an undesirable phenomenon may take place in that the number of errors in the sector exceeds the limit of the correctable errors due to adherence of dust to the recording medium which has accumulated after the recording process. These additional errors will only become detected during ordinary reproduction performed upon a lapse of a predetermined time period after writing, and thus, it becomes impossible to correct the errors by the error-checking code portions. Especially, when using a recording medium having a poor signal-to-noise ratio, e.g., the magneto-optical disk, etc., this effect becomes conspicuous.